The proposed study will analyze the genetic and molecular basis of tissue-specific expression of the gene coding for the aldehyde oxidase in Drosophila ovary. The first phase of this study will focus on the isolation, characterization, and genetic mapping of mutants which alter the expression of this enzyme in ovarian tissue and in other larval and adult tissues. The degree of autonomy in expression of this gene will be examined by means of ovarian, and if necessary, pole cell transplantation. The second phase of this research will analyze the molecular events involved in the expression of the aldehyde oxidase gene in both normal and mutant organisms. For this purpose, the aldehyde oxidase protein will be identified by means of two-dimensional electrophoresis, by immunoprecipitation with anti-aldehyde oxidase-antibody; rates of synthesis of aldehyde oxidase protein in ovarian follicles will be determined by fluorographic analysis of two-dimensional electropherograms. The time of expression of the aldehyde oxidase gene can also be further explored in stage specific egg chambers by measuring the amount of enzyme activity and enzyme protein by these procedures. From these studies, we will be able to establish the genetic location and mode of action of the ovarian specific aldehyde oxidase regulatory gene(s).